Method for Reliable Intermodule Connection in an Infusion System

ABSTRACT

A patient care system is configured for infusing fluid to a patient. The system includes a plurality of modular fluid infusion pumps that each has a connector for connecting to a modular programming unit or to one another. Systems and methods are configured for verifying that the connectors are reliably performing their functions or communicatively connecting the pumps to one another or to the programming unit.

BACKGROUND

A hospital patient often has the need for multiple intravenous (IV)infusions from multiple supplies of fluids, such as drugs. This requiresthe use of multiple infusion pumps that are connected to the patient andto fluid containers via fluid lines. There exist modular infusionsystems in which pump and monitoring modules can be selectivelyattached, both physically and electrically, to a central programmingunit or to one another via one or more connectors. The centralprogramming unit controls the operation of pump modules attached to it,and receives and displays information regarding the pump modules.

The connectors that are used to attach the modules to the centralprogramming unit are typically formed of one or more materials that havegood electrical conductivity. For example, the connectors may be formedof a base metal of high conductivity (such as copper) that is coatedwith a metal that provides protection from oxidation (i.e. such asgold).

The connectors include contact elements that are exposed to theenvironment. The environmental exposure makes the contact elementssusceptible to damage or wear from environmental elements such ascleaners, contaminants, chemicals, fluids, and particulates. Theconnector may also become physically damaged due to normal, mechanicalattachment and detachment of the modules. Moreover, as the connectorswear, the metal coating may remove over time resulting in undesirableexposure of the base metal to the environment.

Such damage and wear to the connectors may lead to a loss of electricalconnectivity or unintended connectivity between connectors. This mayhave negative implications for the patient. There is therefore a needfor systems and methods for verifying the reliability of the connectorin a modular infusion system.

Another common practice is to use circuit breakers on lines to protectagainst short circuits. While this practice can protect against highcurrent short circuits, it can't protect against current shorts that arehigher impedance since the circuit protection must be set at a currentthat is higher than the maximum possible current over all operatingconditions. It is also common practice to provide redundant contacts,however a system with redundant contacts alone would not be able todetect if the redundant contacts have been compromised. After a periodof time, the last redundant contact might fail leading to negativeimplications for the patient. Creating a system that can be switched andtested offline may help to detect failed contacts, but would requirethat the circuit be disrupted in order to test which may only befeasible upon power up. There is therefore a need for systems andmethods for verifying the integrity of connector contacts withoutdisrupting the use of the circuit.

SUMMARY

A patient care system is configured for infusing fluid to a patient. Thesystem includes a plurality of modular fluid infusion pumps that eachhas a connector for connecting to a modular programming unit and/or toone another. Disclosed herein are systems and methods for verifying thatthe connectors are reliably performing their functions orcommunicatively connecting the pumps to one another or to theprogramming unit.

In one aspect, there is disclosed a method for verifying reliability ofa plurality of connector contacts between a first modular pump deviceand a second modular pump device, the method comprising: obtaining ameasurement for each of a plurality of contacts associated with apowered line; comparing the measurements from each contact of a poweredline; and determining whether to affect the operation of the first andsecond pump devices based on the comparison.

In another aspect, there is disclosed a patient care system for infusingmultiple medical fluids, the patient care system comprising: a pluralityof fluid containers each adapted to hold a separate medical fluid; aplurality of fluid lines each in fluid communication with a separatefluid container from among the plurality of fluid containers; aplurality of modular pump devices connected to one another via at leastone connection, each pump adapted to receive and connect to a separatefluid line from among the plurality of fluid lines and to operate on thereceived conduit to pump the fluid from the fluid container connected tothe received conduit; a plurality of electrical current sensorsconfigured to sense electrical currents in power lines and ground linesthat pass through the connector; and a processor connected to theplurality of current sensors and to the plurality of modular pumpchannels, the processor configured to sense an electrical current in atleast two power lines that connect a first modular pump device and asecond modular pump device; sense an electrical current in at least twoground lines that connect the first modular pump device and the secondmodular pump device; compare the sensed currents; and determine whetherto affect the operation of the first and second pump devices based onthe comparison.

The details of one or more variations of the subject matter describedherein are set forth in the accompanying drawings and the descriptionbelow. Other features and advantages of the subject matter describedherein will be apparent from the description and drawings, and from theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a patient care system having four modularfluid infusion pumps, each of which is connected to a respective fluidsupply for pumping the contents of the fluid supply to a patient;

FIG. 2 shows a schematic representation of two modular pumping units,including an example modular pump attached to a modular programmingmodule.

FIG. 3 shows a schematic circuit diagram of a connector interface for apair of connector elements for modular units of the infusion system.

FIG. 4 is an enlarged view of a portion of the patient care system ofFIG. 1 showing two of the fluid infusion pumps mounted at either side ofa programming module, and the displays and control keys of each, withthe programming module being capable of programming both infusion pumps;

FIG. 5 is a perspective view of one of the fluid infusion with its frontdoor in the open;

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

A patient care system is configured for infusing fluid to a patient. Thesystem includes a plurality of modular fluid infusion pumps that eachhas a connector for connecting to a modular programming unit and/or toone another. Disclosed herein are systems and methods for verifying thatthe connectors are reliably performing their functions orcommunicatively connecting the pumps to one another or to theprogramming unit.

As described in detail below, the connector includes a connectorinterface having one or more interconnections elements each associatedwith a connection. A method to measure the state of each interconnectionelement is also disclosed. In this regard, based on information obtainedabout an interconnection element, a decision matrix is applied todetermine actions or inactions related to the state of theinterconnection element.

An example modular infusion pump system is first described withreference to FIG. 1, which shows a patient care system 20 having fourinfusion pumps 22, 24, 26, and 28. A programming module 60 is attachedto infusion pumps 26 and 24. In this regard, each of the infusion pumps22, 24, 26, and 28, as well as the programming module 60, includes atleast one connector element configured to mechanically andcommunicatively connect to a connector element of another infusion pumpor programming module. The mechanical element may be any type ofmechanical connection that is configured to connect a modular infusionpump to another modular infusion pump or programming module.

It should be appreciated that the relative positions and orientation ofthe pumps relative to one another and to the programming module mayvary.

With reference still to FIG. 1, each of the infusion pumps 22, 24, 26,and 28 is fluidly connected with an upstream fluid line 30, 32, 34, and36, respectively. Each of the four infusion pumps 22, 24, 26, and 28 isalso fluidly connected with a downstream fluid line 31, 33, 35, and 37,respectively. The fluid lines can be any type of fluid conduit, such astubing, through which fluid can flow through. Fluid supplies 38, 40, 42,and 44, which may take various forms but in this case are shown asbottles, are inverted and suspended above the pumps. Fluid supplies mayalso take the form of bags or other types of containers. Both thepatient care system 20 and the fluid supplies 38, 40, 42, and 44 aremounted to a roller stand or IV pole 46.

A separate infusion pump 22, 24, 26, and 28 is used to infuse each ofthe fluids of the fluid supplies into the patient. The infusion pumpsare flow control devices that will act on the respective fluid line tomove the fluid from the fluid supply through the fluid line to thepatient 48. Because individual pumps are used, each can be individuallyset to the pumping or operating parameters required for infusing theparticular medical fluid from the respective fluid supply into thepatient at the particular rate prescribed for that fluid by thephysician. Such medical fluids may comprise drugs or nutrients or other.Typically, inter-module connections are used continuously duringoperation for power and communications. The integrity of theseconnections can be critical to ensure that infusions are notinterrupted.

Typically, medical fluid administration sets have more parts than areshown in FIG. 1. Many have check valves, drip chambers, valved ports,connectors, and other devices well known to those skilled in the art.These other devices have not been included in the drawings so as topreserve clarity of illustration.

It should be noted that the drawing of FIG. 1 is not to scale and thatdistances have been compressed for the purpose of clarity. In an actualsetting, the distance between the bottles 38, 40, 42, and 44 and theinfusion pump modules 22, 24, 26, and 28 could be much greater. Therewould be more of an opportunity for the upstream fluid lines 30, 32, 34,and 36 to become intertwined with each other when all four are danglingfrom the bottles, which can cause confusion as to which tube should bein which infusion module. The opportunity for confusion increases as thenumber of tubes increases.

FIG. 2 shows a schematic representation of an example modular infusionpump 24 attached to the programming module 60. The programming module 60includes a connector element 51 that removably attaches to a connectorelement 53 of the modular infusion pump 24. The connector elements 51and 53 may be any type of connector that is configured to connect to oneanother for transmission of electrical and/or communication signals. Theconnector elements may be, for example, male and female type connectorelements made of any of a variety of materials that may include a basematerial and a coating. The infusion pump 24 may have one or moreconnector elements configured to connect to a connector element of oneof the other infusion pumps 22, 26, and 28.

One or both of the infusion pump 24 and the programming unit 60 mayinclude microprocessor, computer memory and software configured toperform a method for verifying a state of the connection between theconnection elements 51 and 53. This enables a modular pump connectorelement with enhanced reliability for critical applications.

FIG. 3 shows a schematic circuit diagram of a connector interface for apair of connector elements 51 and 53 of the infusion system. The diagramshows the connector elements 51 and 53, which can be associated with anyof the infusion pumps 22, 24, 26, 28 or the programming unit 60. Forpurposes of this description, the connector elements 51 and 53 aredescribed as being associated with the pump 24 and programming unit 60,respectively.

With reference to FIG. 3, a power supply 57 is connected to one or morepower lines 59 a, 59 b, and 59 c of the programming unit 60. Likewise, aground 61 is connected to one or more ground lines 63 a, 63 b, and 63 cof the programming unit 60. Each of the power and ground linescommunicates with a microprocessor via a respective sensor 67 configuredto sense electrical current in the line. Any of a variety of components,such as a filter and an analog to digital converter may be supplied asshown in FIG. 3. In addition, the power and ground lines are coupled tothe connector elements 51 and 53 as well as to a power module 71 and areturn or feedback module 73 of the infusion pump 24.

The microprocessor 65 is configured to monitor and report the status ofthe connector elements by analyzing the state of the current through oneor more of the power lines 59 and ground lines 61. The microprocessormay compare current between contacts with the same signal type. Forexample, lines 59 a, b, and c are compared against each other and anexpected range. In this regard, the microprocessor 65 may have access toa decision matrix that is applied to determine actions taken based onthe sensed currents. The microprocessor 65 may be programmed with thedecision matrix or it may access software programmed to achieve thedecision matrix.

According to a first embodiment, the decision matrix is configured toconsider criteria prior to the programming module 60 or the infusionpump 24 starting a critical task, such as pumping fluid into a patient.Based on the criteria, the microprocessor may trigger one or moreactions, such as alerting a user to a condition or requesting actionfrom the user (such as re-connecting the module), or inhibitingoperation of the pump module(s). A first such criteria includesdetermining, based on input received from the current sensors 67,whether at least two power lines 59 and two ground lines 63 have thesame current measurement. This is an indication of redundancy in thepower lines and the ground lines, which is at least one indication of asafe operating condition. If the first criteria is satisfied, then themicroprocessor does not inhibit operation of the modules. Themicroprocessor may optionally send out a signal to the user that theredundancy criteria is satisfied.

A second criteria includes determining whether any short circuits arepresent in the connector elements. The presence of a high currentmeasurement in any of the power or ground lines may be an indication ofa short circuit being present. Another criteria includes determiningwhether an open circuit is present in the connector elements, whichwould be indicated by the presence of a low current in any of the poweror ground lines. If a short circuit or open circuit is deemed present,the microprocessor inhibits operation of the modules and/or sends asignal to a user that a short circuit or open circuit has been detected.The microprocessor may qualify the presence of a short circuit or opencircuit based on a prolonged duration of the high or low current orbased upon a repeated quantity of measurements. In an embodiment, a highcurrent on a single contact would be significantly higher than the othercontacts. A short circuit would be where all contacts are higher thanthe maximum expected current draw for the module. An open circuit on asingle contact would be significantly lower than the other contacts(close to zero current). An open circuit elsewhere would result in allcontacts close to zero current.

After the criteria for starting a critical task has been satisfied andduring operation of the infusion pump, the microprocessor may continueto monitor status of the connections. Based on the monitored status, themicroprocessor may take certain actions, such as to warn or notify theuser that a maintenance action should be taken immediately or should betaken within a predetermined time period. The microprocessor may alsoinstruct a user to disconnect and reconnect one modular pump to anothermodular pump such as to wipe the connections. For example, if an opencircuit or short circuit condition is detected during operation of amodular pump unit, the microprocessor may take such action. Or themicroprocessor may detect a power condition such as lack of power orground redundancy. This permits the user to take the action within anappropriate time period. In the case of a short circuit being detectedon a power or ground line, the microprocessor may trigger a switch thatcauses a shut off the line where the short circuit is present.

It should be appreciated that the microprocessor may be configured withvarious decision matrices configured to act on various conditions in theconnector elements beside power conditions. For example, themicroprocessor may be connected to one or more sensors that sense databeing transferred across data lines in the connector elements. Themicroprocessor may verify redundant communication lines, for example, bycomparing sensed data being transferred across the communication lines.

Exemplary Configuration of Modules

Referring now to FIG. 4, an enlarged view of the front of the infusionpumps 24 is shown attached to the programming module 60. The pumpincludes a front door 50 and a handle 52 that operates to lock the doorin a closed position for operation and to unlock and open the door foraccess to the internal pumping and sensing mechanisms and to loadadministration pump sets or pump cassettes for the pump. When the dooris open, a tube of the pump set can be connected with the pump, as willbe shown in FIG. 3. When the door is closed, the tube is brought intooperating engagement with the pumping mechanism, the upstream anddownstream pressure sensors, and the other equipment of the pump. Adisplay 54, such as an LED display, is located in plain view on the doorin this embodiment and may be used to visually communicate variousinformation relevant to the pump, such as alert indications (e.g., alarmmessages). Control keys 56 exist for programming and controllingoperations of the infusion pump as desired. The infusion pump 24 alsoincludes audio alarm equipment in the form of a speaker.

Other devices or modules, including another infusion pump, may beattached to the right side of the infusion pump 24, as shown in FIG. 1.In such a system, each attached pump represents a pump channel of theoverall patient care system 20. In one embodiment, the programmingmodule is used to provide an interface between the infusion pump 24 andexternal devices as well as to provide most of the operator interfacefor the infusion pump 24.

With reference still to FIG. 4, the programming module 60 includes adisplay 62 for visually communicating various information, such as theoperating parameters of the pump 24 and alert indications and alarmmessages. The programming module 60 may also include a speaker toprovide audible alarms. The programming module also has various inputdevices in this embodiment, including control keys 64 and a bar codescanner (not shown) for scanning information relating to the infusion,the patient, the care giver, or other. The programming module also has acommunications system (not shown) with which it may communicate withexternal equipment such as a medical facility server or other computerand with a portable processor, such as a handheld portable digitalassistant (“PDA), or a laptop-type of computer, or other informationdevice that a care giver may have to transfer information as well as todownload drug libraries to a programming module or pump.

The communications system may take the form of a radio frequency (“RF”)(radio frequency) system, an optical system such as infrared, a BlueTooth system, or other wired or wireless system. The bar code scannerand communications system may alternatively be included integrally withthe infusion pump 24, such as in cases where a programming module is notused, or in addition to one with the programming module. Further,information input devices need not be hard-wired to medical instruments,information may be transferred through a wireless connection as well.

FIG. 4 shows a second pump module 26 connected to the programming module60. As shown in FIG. 1, more pump modules may be connected.Additionally, other types of modules may be connected to the pumpmodules or to the programming module.

Turning now to FIG. 5, an infusion pump 22 is shown in perspective viewwith the front door 50 open, showing the upstream fluid line 30 anddownstream fluid line 31 in operative engagement with the pump 22. Theinfusion pump 22 directly acts on a tube 66 that connects the upstreamfluid line 30 to the downstream fluid line 31 to form a continuous fluidconduit, extending from the respective fluid supply 38 (FIG. 1) to thepatient 48, through which fluid is acted upon by the pump to move fluiddownstream to the patient. Specifically, a pumping mechanism 70 acts asthe flow control device of the pump to move fluid though the conduit.

The type of pumping mechanism may vary and may be for example, amultiple finger pumping mechanism. For example, the pumping mechanismmay be of the “four finger” type and includes an upstream occludingfinger 72, a primary pumping finger 74, a downstream occluding finger76, and a secondary pumping finger 78. The “four finger” pumpingmechanism and mechanisms used in other linear peristaltic pumps operateby sequentially pressing on a segment of the fluid conduit by means ofthe cam-following pumping fingers and valve fingers 72, 74, 76, and 78.The pressure is applied in sequential locations of the conduit,beginning at the upstream end of the pumping mechanism and workingtoward the downstream end. At least one finger is always pressing hardenough to occlude the conduit. As a practical matter, one finger doesnot retract from occluding the tubing until the next one in sequence hasalready occluded the tubing; thus at no time is there a direct fluidpath from the fluid supply to the patient. The operation of peristalticpumps including four finger pumps is well known to those skilled in theart and no further operational details are provided here.

In this particular embodiment, FIG. 5 further shows a downstreampressure sensor 82 included in the pump 22 embodiment at a downstreamlocation with respect to the pumping mechanism. The downstream pressuresensor 82 is mounted to the flow control device 70 and is locatedadjacent and downstream in relation to the flow control device. Thedownstream pressure sensor is located downstream from the flow controldevice, that is, at a location between the patient 48 (FIG. 1) and theflow control device, so that the connection of the correct fluid supplywith the correct pump may be verified before any fluid is pumped to thepatient.

With reference still to FIG. 5, an upstream pressure sensor 80 may alsobe included in the pump 22. The upstream pressure sensor is assigned tothe flow control device or pumping mechanism 70 and, in this embodiment,is further provided as an integral part of the pump 22. It is mounted tothe flow control device 70 and is located adjacent and upstream inrelation to the flow control device. The upstream pressure sensor islocated upstream from the flow control device, that is, at a locationbetween the fluid supply 38 (FIG. 1) and the flow control device, sothat the connection of the correct fluid supply with the correct pumpmay be verified before any fluid is pumped to the patient.

One or more aspects or features of the subject matter described hereinmay be realized in digital electronic circuitry, integrated circuitry,specially designed ASICs (application specific integrated circuits),computer hardware, firmware, software, and/or combinations thereof.These various implementations may include implementation in one or morecomputer programs that are executable and/or interpretable on aprogrammable system including at least one programmable processor, whichmay be special or general purpose, coupled to receive data andinstructions from, and to transmit data and instructions to, a storagesystem, at least one input device (e.g., mouse, touch screen, etc.), andat least one output device.

These computer programs, which can also be referred to programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and can beimplemented in a high-level procedural and/or object-orientedprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium can storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium can alternativelyor additionally store such machine instructions in a transient manner,such as for example as would a processor cache or other random accessmemory associated with one or more physical processor cores.

These computer programs, which can also be referred to programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and can beimplemented in a high-level procedural language, an object-orientedprogramming language, a functional programming language, a logicalprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium can storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium can alternativelyor additionally store such machine instructions in a transient manner,such as for example as would a processor cache or other random accessmemory associated with one or more physical processor cores.

To provide for interaction with a user, the subject matter describedherein can be implemented on a computer having a display device, such asfor example a cathode ray tube (CRT) or a liquid crystal display (LCD)monitor for displaying information to the user and a keyboard and apointing device, such as for example a mouse or a trackball, by whichthe user may provide input to the computer. Other kinds of devices canbe used to provide for interaction with a user as well. For example,feedback provided to the user can be any form of sensory feedback, suchas for example visual feedback, auditory feedback, or tactile feedback;and input from the user may be received in any form, including, but notlimited to, acoustic, speech, or tactile input. Other possible inputdevices include, but are not limited to, touch screens or othertouch-sensitive devices such as single or multi-point resistive orcapacitive trackpads, voice recognition hardware and software, opticalscanners, optical pointers, digital image capture devices and associatedinterpretation software, and the like.

The subject matter described herein can be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. The implementations set forth in the foregoingdescription do not represent all implementations consistent with thesubject matter described herein. Instead, they are merely some examplesconsistent with aspects related to the described subject matter.Although a few variations have been described in detail above, othermodifications or additions are possible. In particular, further featuresand/or variations can be provided in addition to those set forth herein.For example, the implementations described above can be directed tovarious combinations and subcombinations of the disclosed featuresand/or combinations and subcombinations of several further featuresdisclosed above. In addition, the logic flow(s) when depicted in theaccompanying figures and/or described herein do not necessarily requirethe particular order shown, or sequential order, to achieve desirableresults. Other implementations may be within the scope of the followingclaims.

1. A method for verifying reliability of a plurality of connectorcontacts between a first modular pump device and a second modular pumpdevice, the method comprising: obtaining a measurement for each of aplurality of contacts associated with a powered line; comparing themeasurements from each contact of a powered line; determining whether toaffect the operation of the first and second pump devices based on thecomparison.
 2. The method of claim 1, wherein the powered line is apower supply line, power ground line, or analog signal line.
 3. Themethod of claim 1, wherein the measurement is an electrical currentmeasurement.
 4. The method of claim 1, wherein the powered line is adata or digital signal line and wherein obtaining a measurementcomprises collecting data from the line.
 5. The method of claim 3,wherein comparing measurements from each contact of a powered linecomprises determining whether all the currents are substantially thesame.
 6. The method of claim 5, further comprising inhibiting operationof the pump devices if one or more of the currents are not the same. 7.The method of claim 5, further comprising sending a warning to a user ifone or more currents are not the same.
 8. The method of claim 4, furthercomprising sending a warning to a user if all measured currents exceed athreshold.
 9. The method of claim 1, further comprising sending awarning to a user if all measured currents are below a threshold. 10.The method of claim 1, wherein comparing measurements from each contactof a powered line comprises comparing currents in each of a plurality ofpower lines to currents in each of a plurality of ground lines.
 11. Themethod of claim 10, further comprising sending a warning to a user ifall the currents are not the same.
 12. The method of claim 1, furthercomprising requesting a user to disconnect and reconnect the firstmodular pump from the second modular pump.
 13. A patient care system forinfusing multiple medical fluids, the patient care system comprising: aplurality of fluid containers each adapted to hold a separate medicalfluid; a plurality of fluid lines each in fluid communication with aseparate fluid container from among the plurality of fluid containers; aplurality of modular pump devices connected to one another via at leastone connection, each pump adapted to receive and connect to a separatefluid line from among the plurality of fluid lines and to operate on thereceived conduit to pump the fluid from the fluid container connected tothe received conduit; a plurality of electrical current sensorsconfigured to sense electrical currents in power lines and ground linesthat pass through the connector; and a processor connected to theplurality of current sensors and to the plurality of modular pumpchannels, the processor configured to sense an electrical current in atleast two power lines that connect a first modular pump device and asecond modular pump device; sense an electrical current in at least twoground lines that connect the first modular pump device and the secondmodular pump device; compare the sensed currents; and determine whetherto affect the operation of the first and second pump devices based onthe comparison.